The Qualm is a giant mass of tentacles and leaves with hundreds of mouth-like pods lined with teeth. It is about 1/8 of the size of Earth's moon, and it travels through space looking for nutrient rich planets that it can suck dry.
A secret MLM (pyramid) company that offers eternal life, but in fact it transfers the life forces of its members to those position "above". If you get high enough, (meaning you get enough new members) you start to enjoy the benefits. Maybe a willing sacrifice is much more effective for the transfer. But no one says, that a suddenly unwilling member, threatening to tell the authorities, may not loose it involuntarily... thus start people to vanish, and aged corpses are deposited somewhere safe.